The yozizira nsanja phokoso kutchinjiriza chotchinga angatchedwe: kuzirala nsanja phokoso kutchinjiriza chophimba, yozizira nsanja phokoso mayamwidwe mbale, yozizira nsanja phokoso mayamwidwe chophimba, yozizira nsanja phokoso kutchinjiriza chotchinga, etc. Wosakaniza mtundu phokoso mayamwidwe chophimba anatengera, pamwamba ndi mayamwidwe amawu, ndipo magawo otsatirawa ndi mayunitsi otsekereza mawu.Pambuyo pozindikira kutalika ndi kutalika kwa chotchinga cha mawu, kutsika kwa phokoso kwa 10-25dB (A) kutha kupezeka.